INSTANCE

Because it matches RelNode for each input of Union, it
will create O(N ^ 2) matches, which may cost too much during the popMatch
phase in VolcanoPlanner. If efficiency is a concern, we recommend that you
use AGG_ON_FIRST_INPUT and AGG_ON_SECOND_INPUT instead.

Method Detail

onMatch

Receives notification about a rule match. At the time that this method is
called, call.rels holds the set of relational
expressions which match the operands to the rule;
call.rels[0] is the root expression.